There is little scientific evidence that describes the cycle-to-cycle variation of the laryngeal tissue vibratory pattern or the potential impact of upper airway temperature changes on laryngeal tissue function throughout the menstrual cycle. Women have a significantly higher prevalence of voice disorders than men and receive clinical advice to avoid voice use prior to menstruation for avoidance of vocal injury, indicating a possible correlation between cyclical hormonal fluctuations and voice function. Discovery of laryngeal mechanical differences through the menstrual cycle may help identify time points of vocal vulnerability that may predispose women to develop voice disorders. The interrelatedness of temperature, direct physiologic measurements, and hormones has not been systematically studied in prior investigations of voice function. The interdisciplinary design of the proposed research will investigate the influence of hormone fluctuations associated with the menstrual cycle on physiological measurements of vocal function. This novel application of concurrent measures of hormones and upper airway temperature with clinical measures of vocal function allows for systematic study of the effect of hormone fluctuations and upper airway temperature on vocal tissue function. The hypothesis of this study is that there will be differences observed i vocal function measures that can be attributed to hormonal fluctuations associated with different phases of the menstrual cycle, with the ovulation and ischemic phases being the most vulnerable periods. This work has two specific aims: 1) To determine if vocal function, upper airway temperature and self-identified periods of vocal vulnerability or increased perceived effort correlate with hormonal levels across four different phases of the menstrual cycle. 2) To determine if the vocal function of premenopausal women differs from postmenopausal women. Given the anatomical and physiological challenges of accessing the laryngeal tissues, measurements of upper airway temperature and vocal fold tissue function during different phases of the menstrual cycle will contribute to our understanding of the influence of hormonal fluctuations on voice function. Identification of specific hormonal influences on voice function wil improve our understanding of vocal physiology, leading to improved clinical guidance for reducing or avoiding voice disorders in women who are known to be vulnerable to vocal fatigue and pathology.